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(No Model.) A 6 Sheets-Sheet 1.

M. CRAWFORD.

APPARATUS FOR EXTRAGTING PRECIOUS METALS FROM THEIR ORES.

No. 543,675. Patented July 30, 1895.

INVENTOR Mar W f (No Model.)

6 Sheets-Sheet 2. M. CRAWFORD. APPARATUS FOR EXERAGTING PRECIOUS METALSFROM THEIR 01128. No. 543,675. Patented July 30, 1895.

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M. CRAWFORD. APPARATUS FOR EXTRAGTING PRECIOUS METALS FROM THEIR 033s.No. 543,675. Patented July 30, 1895.

INVENTOR (No Model.) 6 Sheets-Sheet 5.

, GRAWFORD. APPARATUS FOR EXTRAGTING PRECIOUS-METALS FROM THEIR ORES.

No. 543,675. PatentedJuly 30, 1895.

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INVENTOR .(No Model.) 6 Sheets-Sheet 6.

M. CRAWFORD. APPARATUSFQR EXTRAGTING PRECIOUS METALS mom THEIR 0311s;

No. 543,675. Patented July 30, 1895.

m Mtg F T Q 1 m a 9 5 L E R 6 TNESS/E? 7 v INVENTOR UNITED STATES PATENTOnnron.

MIDDLETON CRAWFORD, OF COLORADO SPRINGS, COLORADO, ASSIGNOR OFTHREE-FOURTHS TO THOMAS C. PARRISH AND DUNCAN CHISHOLM, OF SAME PLACE,AND JAMES POURTALES, OF SILESIA, GERMANY.

APPARATUS FOR EXTRACTING PRECIOUS METALS FROM TH EIR ORES.

SPECIFICATION forming part of Letters Patent No. 543,675, dated July 30,1895.

Application filed December 14, 1894. Serial No. 531,751. (No model.) I

To all whom it may concern: Be it known that I, MIDDLETON CRAWFORD, asubject of the Queen of Great Britain, (but having declared 'myintention of becoming a 5 citizen of the United States,) residing atColorado Springs, in the State of Colorado, have invented a certain newand useful Apparatus for and Process of Extracting Precious Metals fromTheir Ores, (Case D,) whereof the follow- I ing is a specification,reference being had to the accompanying drawings.

My invention has reference to apparatus employed in solution processesfor the extraction of the precious metals as distinguished I from thoseprocesses which employ only amalgamation and concentration. Theapparatus comprises five groups of mechanism, which are preferably usedin combination with each other and in substantially the order hereinafter set forth. When so used they render it practicable to continuouslycirculate the solvent liquid, the precious metals being dissolved at onepoint in this circulation and reclaimed .at another point, and thesolvent liquid'being finally restored to its original efficiency.Certain of the devices orgroups of devices are, however, capable ofbeing used independently of theother groups in connection with which Ihave shown them for the purpose of illustrating my continuous process.

The groups of devices above referred to are as follows: first, devicesfor agitating the powdered ore with the solvent liquid; second, devicesfor subjecting the resultants of the solution process to an amalgamatingprocess; third, devices for separating the solid portions of theresultants of the amalgamating process from their accompanying liquids;fourth, devices for removing the precious metals which are in solutionfrom the solvent liquid which contains them; fifth, devices for causingthe continuous circulation of the solvent liquid.

In the accompanying drawings, Figure 1 illustrates in conventionalelevation the col- 4 5 location of the various groups of devices justmentioned, whereby they may be employed in a continuous process. Fig. 2is a plan view of the agitating a d amalgamating machinery. Fig. 8 is aside e ovation of the same.

Fig. 4 is an end elevation from the right of Fig. 1. Fig. 5 is asectional view of one of the agitating barrels. Fig. 6 is a centrallongitudinal section of' the amalgamating-table. Fig.7 is across-section of the same along the line .2 2, Fig. 6.

The agitating and amalgamating devices are both mounted on the sameframework A A of heavy timbers. The main drivingshaft B is carried bybearings in these timbers and imparts motion to both of these devices.This shaft is driven from the fast and loose pulleys b b and carriesnear its left-hand end two broad pulleys 1) 19 Two countershafts C Ccarry fast and loose pulleys 0' 0 through which they are drivenrespectively from the pulleys 11' b Upon both shafts C C are situatedsmall gear-wheels c c, and each of these gear-wheels meshes with a largegearwheel 07, mounted upon the axle of a rotating barrel D, which axlesare mounted in suitable bearings in the framework A A. The barrels areprecisely alike and are so constructed as to presentinteriorly nometallic surface which might be afiected by the action of the solventliquid which they contain. To this end the barrel is constructed ofheavy oaken staves. At each end the head is formed interiorly of a'solidpiece of the same material. Exteriorly to this wooden head is a solidiron circular plate carrying alarge trunnion at its center, the trunnionbeing braced to the plate by a series of triangular radial webs d. Theplate is not united to the wooden head against which it lies by any the.tallic bolts,but is held in position by the overlapping edges of thechine within a deep groove in which its edges fit. The two trunnionsform the axles of the barrels. The trunnion of each barrel which issituated at the opposite end from the gearing mechanism is hollow, andcorresponds interiorly to an aperture in the wooden head and exteriorlyto a pipe E, through which communication may be had at all times to theinterior of the barrel, even though it be in revolution.

Upon the opposite side from the aperture F, and near the left-hand endof the barrel, a series of small holes is drilled through the peripheryof the barrel. These holes are of varying diameter, and are closed bysuitable plugs. They may be seen at G G, Fig. 5.

Below the level of the two rotating barrels is an amalgamating-table II.It is hung from above by flexible rod-hangers 72, and is of sul'licientsize to receive the entire contents of either barrel. To the lower sideof this table are attached the connecting-rods h h, mounted upon theeccentrics 71.2 k upon the main shaft B, by the revolution of which acontinuous vibratory motion is imparted to the table. The upper surfaceof this table is covered with an amalgamating-plate and its edges aresufficiently high to prevent its contents from being thrown over them inany direction. The surface of this amalgamatingplate is perfectly levelwith respect to the direction in which the table vibrates, but slopesslightly upward toward its right'hand edge, as seen in Figs. 2, 3, and6. Along this edge runs the overflow-trough 7L3, the bottom of whichslopes downwardly from either end to the exit-pipe h.

The operation of the groups of devices which have so far been describedis as follows: The powdered ore from the stamp-mill is introducedalternately into one or other of the barrels through the large apertureF and the cover tightly replaced; The solution wherewith it is desiredto lixiviate the ore is then introduced into the barrel through the pipeE. This solution in Fig. 1 is contained in the storage-tank N, fromwhich it is led out by the pipe 6, which communicates by a two-way cockwith either of the pipes E. The ore and the lixiviating-liqnid havingbeen introduced into the barrel the mechanism for revolving the barrelis set in motion. \Vhe'n the revolution'has proceeded for the requisitelength of time, one of the plugs closing the small holes G G is removed.The revolution is then continued, and at each turn of the barrel acertain portion of its contents is discharged through this small holeinto the amalgamating table below. From among the diiiferent small holesG G, of which, as has been stated, the diameters vary, that one ischosen for opening which, having reference to the varying fineness ofthe contents of the barrel, will allow the entire contents to bedischarged during a period of revolution precisely equal to that whichis required to complete the lixiviating process in the barrel before theplug has been removed from the aperture G. While one of the barrels isrotating and emptyingitself of its contents the other one is filled anewwith ore and solution and rotated for the purpose of lixiviation. Thebarrels are thus continuously emptied alternately, so that at all timesthere is a fresh supply of lixiviated ore falling upon theamalgamating-table. If desirable more than two barrels may be used,

the machinery which has been described being simply duplicated for thatpurpose. This may be necessary when the time required for completelixiviat-ion is long, but in case it is short, say about one hour, twobarrels are quite sufficient. The amalgamatiug-table is kept incontinuous vibration by the revolution of the shaft B. The drippingsfrom whichever one of the barrels is emptying itself 0t its contentsfall continuously near the lefthand end of the table, as seen in Fig. 6,and continuously work their way over the amalgamating-surface up theslight incline and over the edge into the overflow-trough 7L3. Inpassing over the amalgamating-sun face any coarse gold which thelixiviating solution has been unable to dissolve comes into contact withthe mercury and is reclaimed; and as the solvent action of thelixiviating solution, even though it has not dissolved the gold, will atleast have brightened its surface, the efficiency of theamalgamating-plate is to this extent rendered the more complete bycombining the two processes in the order described. From theamalgamating-table the gangue and the soln tion pass, by means of theexit-pipe h", directly into the tank I. This tank has sloping sides, andfrom its bottom along one of these sides runs a screw-separator J. Thisconsists of the shaft j, driven by a belt-pulley j. Around this shaftruns the screw-"thread j having a width of two or three inches and apitch of about one turn to the foot. The screw-conveyer continues forsome distance beyond the edge of the tank I and is surrounded by acasingj The space between the inner edge of this casing and the outeredge of the screw-thread is sufficientl y great to allow any liquidwhich may be carried up out of the tank[ by the conveyor to run back.The continuous revolution of this separator continually withdraws thesolid material from the bottom of the tank I and delivcrsit at its topinto the filter-car K, while at the same time an exit-pipe 'i removesthe excess of solvent liquid continuously from the top of the tank I anddelivers it into .a second tank L. The filter-car is mounted upon atrack directly over the tank L and is one of several which are used inalternation. It contains a canvas bottom, through which any of thelixiviating liquid which may have been car ried up by thescrew-separator is allowed to slowly percolate into the tank L. Ifdesirable this percolation may be increased by throwing a small quantityof water from time to time upon the surface of the contentsof the car bya hose. Whenever the car K is full of tailings it is run off and anothersubstituted in its place. From the tank L the solotion is pumpedcontinuously, by a pipe Z and pump Z, up to a receptacle M, where theprocess for removing the precious metal from the solution iscontinuously carried on. In Fig. 1 electrodes at m, with suitableconnections, are shown within this receptacle, by means ITS of which theseparation may be effected electrically. When the precious metal hasbeen removed from the solution it runs over into the large storage-tankN, from which the solution is drawn off continuously for use over againin the lixiviating-barrels. the process of its withdrawal from this tankand return thereto, its efficiency has been weakened, the necessarymeans for restoring the efficiency, whether the addition of chemicals orthe application of an electric current, may be here employed.

The advantages of the apparatus which has been described are derivedfrom the contin uity of the solution process, from the ready andcontinuous extraction of the tailin gs from the solvent liquid, andparticularly the completeness of this extraction, and finally from thecontinuous circulation of the solvent liquid, whereby almost none of itis lost, but it is used over and over again.

Having thus described my invention, I claim-- 1. An apparatus forextracting precious metals from their ores, which consists in thecombination of a plurality of revoluble lixiviating barrels; a singleamalgamating table upon which they all discharge their contents; andmeans for causing the barrels to discharge successively in regularalternation, substanamalgamating table upon which they all dischargetheir contents; and means whereby the said discharge iseffectedcontinuously from one barrel at a time in regular alternation,substantially as described.

3. An apparatus for extracting precious metals from their ores, whichconsists in the combination of a plurality of revoluble lixiviatingbarrels each containing a discharge opening; a single amalgamating tablesituated beneath the series of barrels over one end of which all of thedischarge openings of the barrels are situated, and an overflow troughsituated along the opposite end of said amalgamating table, into whichthe contents of the barrels pass a fter having traversed the surface ofthe amalgamating table, substantially as described.

If, during 4. An apparatus for extracting precious metals from theirores, which consists in the combination of a plurality of revolublelixiviating barrels each containing a discharge opening; a singleamalgamating table situated beneath the series of barrels, over one endof which allot the discharge openings of the barrels are situated; anoverflow trough extending along the opposite end of said amalgamatingtable into which the contents of the barrels pass after having traversedthe surface of the amalgamating table; and means for imparting to saidamalgamating table a continuous vibratory motion at right angles to theline along which the contents of the barrels cross the table,substantially as described.

5. An apparatus for extracting precious metals from their ores, whichconsists in the combination of a tankwherein the solvent liquid isstored; a revoluble lixiviating receptacle; a pipe running from saidstorage tank to the lixiviating receptacle; an amalgamating table; meansfor causing the lixiviating receptacle to discharge its contentscontinuously upon the amalgamating table; a separating tank; means forconducting ore which has passed over the amalgamating table into theseparating tank; means for separating the solid contents of thisseparating tank from its liquid contents; a third tank; connectionswhereby the solvent liquid thus separated is passed to said third tank;means for reclaiming the precious metals from the solution in said thirdtank; and connections whereby the solvent liquid is run from the thirdtank to the storage tank, substantially as described. I

6. 'A separator for removing the tailings of the ores of precious metalsfrom their accompanying solvent solution, which consists in thecombination of a tank into which the ores and solution are discharged; aconveyer running from the bottom of said tank to a point exteriorthereto by which the solids are separated from the liquids; a car filterwith a permeable bottom situated below the discharge end of theconveyer; and a second tank below said car filter, substantially asdescribed.

MIDDLETON CRAWFORD. Witnesses:

S. O. MILLS, W. E. POULTON.

